La Piedad

La Piedad de Cabadas is a city and its surrounding municipality (La Piedad municipality) located at Coordinates: 20°20′N 102°01′W / 20.333°N 102.017°W / 20.333; -102.017 in the north-west of the Mexican state of Michoacán, bordering Jalisco and Guanajuato. The original colonial name was San Sebastián. It is bordered by the town of Santa Ana Pacueco, Guanajuato. Both towns straddle the Lerma River. La Piedad's population was 99,837 inhabitants in the 2010 census (250,000 including its metropolitan area). The municipality has an area of 284.11 km² (109.7 sq mi). It is bordered by the states of Jalisco and Guanajuato.

Limits

La Piedad, "north door" of the state of Michoacán, surrounding the Lerma river, has limits at the north with the municipalities of Degollado, Jalisco and Pénjamo, Guanajuato; at the east with the municipality of Numarán, Michoacán; at the south with the municipalities of Zináparo, Churintzio, and Ecuandureo, Michoacán; and at the west with the municipality of Yurécuaro.

C.F. La Piedad

Club de Fútbol La Piedad is a Mexican football club based in La Piedad, Michoacán. The club currently plays in the Liga Nuevo Talentos de Mexico in the Segunda División. Reboceros was founded in 1951 by football players from "Perros Bravos" neighborhood, most of them were craftsman working with leather and textile.

History

The club was founded in 1951. In 2001 the club won the Verano 2001 championship.

In June 2009, an Ascenso MX football club from the neighboring province of Guanajuato, Petroleros de Salamanca, relocated to La Piedad. The club changed its name to Club de Fútbol La Piedad, and four years later the club was promoted to Liga MX after defeating Neza FC in a promotion play-off. The club had asked permission to relocate from La Piedad before the new season began. The club was subsequently sold and its over sixty-year history ended when the new owners from Veracruz decided to liquidate the club to use its Liga MX license for their Ascenso MX team Tiburones Rojos de Veracruz.

Difluoroacetylene

Difluoroacetylene, C₂F₂, is a compound of carbon and fluorine. A linear molecule, its two carbons are joined by a triple bond and have terminal fluorines: F-C≡C-F. The molecule is the perfluorocarbon analog of acetylene, C₂H₂. Preparation of difluoracetylene is difficult, with danger of explosions and with low yields. Nevertheless, the compound has been made, isolated, and characterized by NMR and IR spectroscopy. The compound is of interest as a precursor to fluoropolymers containing double bonds, analogous to polyacetylene.

Bibliography

Comet Yi–SWAN

Comet C/2009 F6 (Yi–SWAN) is a non-periodic comet which appeared in March 2009.

It was first discovered by Korean amateur astronomer Dae-am Yi on March 26, 2009, using a Canon 5D camera and 90-mm lens. It is believed to be the first comet discovered by a Korean in the modern age. Independently, on April 4 Rob Matson reported he had discovered a comet in the SWAN instrument photographs on the SOHO (Solar and Heliospheric Observatory) spacecraft website.

The comet was not bright enough to be seen by the naked eye, but was theoretically visible through amateur telescopes. However, it was harder to see than predicted, as it remained quite small and did not form much of a visible tail. It reached a peak magnitude around +8.5 in April into May, and passed 1.5 degrees south of the Double cluster in Perseus on April 23.

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Hexafluoroethane

Hexafluoroethane is a fluorocarbon counterpart to the hydrocarbon ethane. It is a non-flammable gas negligibly soluble in water and slightly soluble in alcohol.

Physical properties

Hexafluoroethane's solid phase has two polymorphs. In the scientific literature, different phase transition temperatures have been stated. The latest works assign it at 103 K (−170 °C). Below 103 K it has a slightly disordered structure, and over the transition point, it has a body centered cubic structure.

Table of densities:

Vapor density is 4.823 (air = 1), specific gravity at 21 °C is 4.773 (air = 1) and specific volume at 21 °C is 0.1748 m³/kg.

Uses

Hexafluoroethane is used as a versatile etchant in semiconductor manufacturing. It can be used for selective etching of metal silicides and oxides versus their metal substrates and also for etching of silicon dioxide over silicon. The primary aluminium and the semiconductor manufacturing industries are the major emitters of hexafluoroethane.

Together with trifluoromethane it is used in refrigerants R508A (61%) and R508B (54%).